1. Field of the Invention
The present invention relates to a motor control device, an image processing apparatus, and a motor control method.
2. Description of the Related Art
In image processing apparatus, a stepping motor has been widely used for a part where a rotation position control is required. The stepping motor can easily achieve rotation position control.
Conventionally, a drive efficiency of the stepping motor has been low. Therefore, instead of the stepping motor, a motor configured to utilize a permanent magnet as a stator and a coil as a rotor has been used for some components. As an example of the motor, a direct current (DC) motor has been known. The DC motor generates a rotating force with a magnetic attractive force or a magnetic repulsive force generated by alternating direction of a current flowing into the rotor (see Japanese Patent Laid-open Publication No. H5-313059, which is incorporated herein by reference).
However, a drive control of the stepping motor is different from that of the DC motor. Thus, when a component driven by the stepping motor is driven by the DC motor (i.e., when the stepping motor is replaced with the DC motor), it is necessary to detect a rotation position of a rotation shaft of the DC motor and perform position control. This leads to a duty of an accurate motor control.
Generally, the position information of the rotation shaft of the DC motor is obtained as pulse signals through an encoder. The obtained position information is formed of a discrete value. The speed information calculated by differentiating the position information provides a pulse-like waveform. The control operation based on the speed information leads deterioration of accuracy of motor control. When a control unit implements a discrete system, missing of feedback information occurs due to aliasing signal processing, so that further it leads the deterioration of accuracy of motor control.
Therefore, there is a need for a motor control device, an image processing apparatus, and a motor control method that can prevent the deterioration of accuracy of motor control associated with replacement of motors.